Apparatus for treating material with silent electric discharges



Feb. 27, 1940. G. MATHESON APPARATUS FOR TREATING MATERIAL WITH SILENT ELECTRIC DISCHARGES Filed April 19, 1935 2 Sheets-Sheet 1 Feb. 27, 1940. e. L. MATHESON APPARATUS FOR TREATING MATERIAL WITH SILENT ELECTRIC DISCHARGES 2 Sheets-Sheet 2 Filed April 19, 1935 lNS/DE TUBE DNTREA TED sunny TANK FEED ZINE COOLING LI UID sromc' Patented Feb. 27, 1940 PATENT OFFICE APPARATUS FOR TREATING MATERIAL WITH SILENT ELECTRIC DISCHARGES George L. Matheson, Union, N. 3., assignor'to Standard Oil Development Company, a corporation of Delaware Application April 19,

2 Claims.

This invention relates to the treatment of hydrocarbon material with silent electric discharges and is more particularly concerned with improvements in the apparatus therefor.

The process of treating materials with silent electric discharges is frequently called voltolization. It consists in subjecting oil, Wax or other material to be treated to the action of a high frequency high potential alternating current which discharges between electrodes coated with a thin film of the material to be treated while maintained under vacuum or in a rarefied gaseous atmosphere.

The voltolization of hydrocarbon oils and waxes causes the same to become greatly thickened. The effect is believed to be one of polymerization. High molecular weight polymers of greatly increased viscosity are produced.

It has been found that the rate of thickening is proportional to the electrical power input. Thus the output of a particular apparatus may be doubled by doubling the power input. However, increasing the rate of power .input causes the temperature of the oil to rise and a high temperature is detrimental to the dielectric material employed and in many cases to the thickening process itself. It is the object of the present invention to provide an apparatus which will make possible the use of high power inputs without encountering the difiiculties due to increased temperature. This is accomplished by continually cooling the electrodes during the operation.

Figs. 1, 2 and 3 are illustrations of a suitable oscillator nozzle in which Fig. 1 is a top view, Fig. 2 is a side view, and Fig. 3 is a top view of a detail. Fig. 4 is a semi-diagrammatic view in sectional elevation of the apparatus.

The nature of the improved apparatus and the manner in which it operates will be fully understood from the following description read with reference to the accompanying drawings which are semi-diagrammatic views in sectionalelevation of one type of apparatus suitable for the purposes of the present invention.

Referring to the drawings numeral I designates a cylindrical tube made of a conducting material preferably a metal. The outside of the tube is coated with a 50116. organic dielectric material. This element comprises one electrode and is grounded at A by means of lead wire 2. Tube I is disposed concentrically within a larger tube 3 made of or coated on the outside with a conducting material such as ametal. The inside of tube 3 is lined with a dielectric material which may be similar to or different from-that used on 1935, Serial No. 1736i the inner electrode. The outer tube 3 comprises the second electrode and is connected by means of lead wire 4 to a source of high frequency high potential alternating current.

The clearance between tubes l and 3; should be 5 substantially uniform all around and preferably about 3 to 6 millimeters.

The outer tube 3 is surrounded with a jacket 5 adapted to be supplied continuously with a stream of cooling fluid. Each end of tube 3 is insulated 10 by means of rings 6 made of slate or other suitable dielectric material. Gaskets of fibre or similar material may be used to make these joints tight.

The lower end of tube l is closed. The lower 15 end of tube 3 opens into a vessel 1 preferably made with concave ends to withstand the high vacuum maintained inside. Vessel I may be lined with glass or enamel or some other material to prevent contamination of the material un- 2 dergoing treatment. One end of vessel 1 is connected by means of pipe 8 to a vacuum. pump (not shown).

A pipe of small diameter designated by numeral 9 extends within and nearly to the bottom of tube 5 I. This pipe is adapted to be supplied continuously with a stream of cooling fluid.

' The operation of the apparatus is as follows: Cooling fluid, the nature of which will be more clearly defined below, is withdrawn from a sup- 0 ply tank l0 through line II by means of pump l2, flows through line I3 into and through a cooling coil I4, and thence through line I5 into the bottom portion of jacket 5. The liquid flows upwardly through the jacket 5 and flows out 5 through line I6 and returns to the cooler II through lines I1 and I3. I

Another stream of cooling fluid flows through line I8, which branches ofi from line I5, and enters the small pipe 9-within the tube l. The liqo uid flows through the pipe 9 to the bottom of tube I and then flows upwardly around the pipe 9 and returns to the cooler through lines I9, I1 and I8. In this way both the electrodes I and 3 are continuously cooled. a

The oil or wax or other material to be treated is contained within vessel I provided with a heating or cooling means (not shown). The

level of the liquid is maintained at a point indicated by numeral 20. Oil is withdrawn from 50 vessel 1 through line 2| by means of pump 22 and forced through line 23 into the inside of tube 3. The oil fiowsdownwardiy through tube 3 in the annular space between the two electrodes.

The oil may be introduced into the tube 3' through spray nozzles 24 or any other suitable device for distributing the oil in a fine spray.

For this purpose, it is convenient to use a type of oscillating nozzle which will periodically direct a spray of oil against the walls of the tube 3, thereby to wash down any material which tends to adhere thereto. One suitable oscillating type of nozzles is illustrated in drawing 2. Figure 1 is a top view of the apparatus, Figure 2 is a side View of the apparatus, while Figure 3 is a detailed top view of the cammed guide 53, showing the cam 54. A means 50 imparts oscillating motion to the feed inlet line, and to the nozzle bracket 24A, to which the nozzles 24 are attached by universal connections 52 which allows the nozzles to swing freely perpendicularly to the electrodes. The oscillating motion of the nozzle support 24A causes the nozzles to slide back and forth in a fixed cam bracket 53, which causes the nozzles to spray periodically upon the two walls of the electrodes in the annular space between the same.

As the oil flows down through the tube 3, it is exposed to the action of silent electric discharges which discharge between the electrodes I and 3. The oil returns to the vessel I and may be recirculated as many times as necessary to obtain a product of the desired characteristics and viscosity. The fully treated product'may be drawn ofi from vessel 1 through lines 2| and 25.

Frequently, after the treatment has continued for some time, it is desirable to introduce fresh untreated material into the system, or even to introduce some entirely different material. This may be done by withdrawing the said material from a supply tank 26, through a heating or cooling means (not shown), then through line 21 and forcing the same through lines 28 and 29 by means of pump 30 into the nozzles 24.

The voltolization may be carried out in the presence of a gas which may either be inert or have some reactive effect on the oil. Such gas may be withdrawn from a supply tank 3| through line 32 and sucked into vessel 1 or may be introduced directly into the feed nozzles through lines 36 and 23, the feed line being conveniently made oscillatory as described with regards to Figure 1, and in which case, the feed line into tube 3 passes through a packed attachment 5| to prevent external gas from entering the vacuum space. This gas may be recirculated through the apparatus by means of line 33 and blower 34. Gases such as hydrogen, oxygen, nitrogen and the oxides, oxides of carbon, formaldehyde, chlorine or other halogens or hydrogen halides, hydrocarbons such as cracked refinery gases, propane, acetylene, ethylene, and butadiene, cyanogen, ammonia, steam, ozone, sulfurous gases such as sulfur dioxide, sulfur trioxide, hydrogen sulfide, carbonyl sulfide, etc., and "the like may be used. It is preferable in most cases to carry out the voltolization in a rarefied atmosphere of hydrogen.

Additional cooling may be obtained by introducing through the nozzles 24 together with the feed stock readily vaporizable materials or materials which will be vaporized at the low pressure maintained. As examples of such materials may be mentioned liquefied hydrocarbon gases, such as propane and butane, naphtha, liquid sulfur dioxide and the like. These materials by vaporizing under the low pressure of the voltolizer chill the oil undergoing voltolization as well as aiding in film formation by increasing foaming of the reaction mixture,

In the operation of the process, the cooling fluid used to cool the electrodes by circulation employed and the like.

tions of various salts may also be used as the cooling liquid if at the points B and C lengths of rubber tubing or other insulating material 10 wound around an iron core to form choke coils are inserted. If salt solutions are used it is advantageous to add glycerine or similar higher boiling liquids to the solution.

Although it is preferable to use as cooling 1:; liquids, materials which will not boil at the operating temperature of the voltolizer, lower boiling liquids may be used if a means for condensing the vapors is provided. For example a cooling coil may be provided to act as a reflux coil 0 for vapors formed in the cooling spaces surrounding the electrodes.

It is also possible to use gases as the cooling fluid. For example a stream of air, nitrogen,

carbon dioxide, steam, vaporized hydrocarbons or 25 other compounds may be circulated through the cooling jackets in contact with the electrodes. In many cases a liquid may be used to cool the inner electrode while the outer electrode may be cooled by blowing a gaseous cooling medium over 30 the surface of the outer electrode which may be provided with suitable means such as grooves or fins to dissipate the heat more rapidly.

The conducting portion of the electrodes may be made of metals, metal alloys, carbon, graphite, material known under the trade-mark Aquadag, or any other material that will conduct electricity. As examples of suitable metals may be mentioned iron, aluminum, copper, nickel, tungsten, vanadium, platinum, nickel 40 steel alloys, such as those having the same-coeflicient of thermal expansion as the dielectric The metallic or conduct-' ing material may be in the form of foil, mesh screen or sheets wrapped around a dielectric material; or the metal may be sprayed, sputtered, plated or deposited upon the dielectric material. The entire tube may of course be made of metal.

The dielectric material may be selected from a great variety of materials, the particular one being selected depending upon its adaptability for fabrication, capacity to withstand high tension current under operating conditions, availability and expense. As examples of suitable solid organic dielectric materials may be mentioned wood, wood fibre, paper, compressed or gibraltarized paper, sealing wax, hard or insol-- uble waxes such as carnauba wax, textile materials such as silk, linen, cotton, wool, natural or synthetic resins such as those known under the trade-marks Bakelite and Pertinax, urea formaldehyde, cumarone-indene, vinyl acetate or vinyl chloride, petroleum resins and other resinous materials, naturalor synthetic rubber or rubber compositions, polymers such as those known under the trade-marks Duprene, Pliolite, Plioform and the like, linoleum, starch, dextrin, amber, lacquers, cellulose derivatives such as cellulose acetate, regenerated cellulose, and benzyl cellulose, sulfurized polymers, of the type known under the trade-mark Thiokol, vulcanized rubber, vulcanized fibre, etc. Various binding materials such as resins, glue, drying oils, varnishes and the like may be used to cause the dielectric material to adhere to the conducting portion of the electrode.

The voltage of the current used may vary from as low as 500 volts to as high as 10,000, 20,000 or more volts. The frequency may vary from 500 to 50,000 or more cycles. The vacuum maintained may vary from .9 of an atmosphere to a fraction of a millimeter absolute pressure.

The apparatus described herein makes possible the use of high electrical power inputs without encountering excessively high temperatures and thus greatly increases the capacity of the voltolizer and shortens the time necessary for treating.

It will be understood that various modifications may be made without departing from the spirit and scope of the invention, which is not limited by any theories of the mechanism of voltolization nor by any details given merely for purposes of illustration but is limited only in and by the following claims in which it is intended to claim all novelty inherent in the invention.

I claim:

1. Apparatus for subjecting hydrocarbon material to the action of silent electric discharge without causing an excessive rise in temperature which comprises two concentrically disposed tubular conducting metal electrodes, said electrodes being coated with solid organic dielectric materials adherent thereto so as to fully prevent any contact of material treated with said conducting electrodes, a jacket surrounding the outer electrode, a pipe extending into the inner electrade, means for circulating a cooling liquid through the jacket and the inner electrode to maintain the electrodes and the organic dielectric materials at a uniform temperature, oscillating nozzles for introducing hydrocarbon material into the upper end of the annular space between the electrodes, means -for insulating the jacket from the outer electrode, means for maintaining the annular space under vacuum, and means for recirculating the hydrocarbon material through the annular space.

2. Apparatus for subjecting liquid hydrocarbon material to the action of high tension silent electric discharges which comprises two vertically and concentrically disposed conducting metal electrodes, coatings of solid organic dielectric material adhering to the adjacent surfaces of said conducting electrodes and forming the walls of an annular discharge space so as to fully prevent any contact of material undergoing treatment with said metal electrodes, means for circulating cooling fluid in contact with the opposite walls of the electrodes to prevent excessive rise in temperature of the conducting electrodes and their coatings, means provided at the one end of the annular space for directing liquid hydrocarbon material to be treated against a dielectric wall of the annular space so as to flow downwardly forming on said wall a thin film of the hydrocarbon material, and means for withdrawing products from the other end of said annular space.

GEORGE L. MATI-IESON. 

